Apparatus for robotically inspecting gas turbine combustion components

ABSTRACT

A robotic inspection system for gas turbine combustion components includes an exterior manipulator for visual inspection of the exterior surface of the impingement sleeve, an interior manipulator for visual inspection of the interior of the transition piece body and an annulus manipulator for inspecting the side weld seams of the transition piece body. The exterior manipulator includes an arcuate segment extending about the annular spaced impingement sleeves and a robotic subassembly including a linear rail and an upper arm and forearm mounting an inspection head pivotally coupled to one another for visual inspection of the top, bottom and side external surfaces of the impingement sleeve. The interior manipulator mounts to the open end of the combustion casing and includes an arm mounted for universal pivotal movement to the mount, actuators for pivoting the arm and motors for extending and rotating an inspection head about pan and tilt axes within the interior of the transition piece body. The annulus manipulator includes a guide plate mounted to the combustor casing and having contoured surfaces tracking the side weld seams. A carriage mounts an inspection head and tracks along the contoured surfaces to track along the seam, affording remote visual inspection thereof.

RELATED APPLICATIONS

This application is a divisional of application Ser. No. 09/739,356,filed Dec. 19, 2000, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

The present invention relates to a robotic inspection system for in situinspection of gas turbine cannular combustion components for the purposeof evaluating the condition of the components.

Maintenance costs and equipment availability are two of the mostimportant concerns of a gas turbine operator. Proper maintenance isrequired to minimize equipment downtime and provide long-term reliableoperation. Maintenance inspections of gas turbines are broadlyclassified as standby, running and disassembly. Disassembly inspectionsare generally categorized into three types: combustion inspection, hotgas path inspection and major inspection. All three types of inspectionsrequire shutdown and disassembly of the turbine to varying degrees toenable inspection and replacement of aged and worn components. Thecombustion inspection includes evaluation of several components of thecombustion system including the transition piece. The transition pieceis a thin-walled duct used to conduct high-temperature combustion gasesfrom the combustion chamber to the annular turbine nozzle passage. Thetransition piece and other combustion components are generally inspectedfor foreign objects, abnormal wear, cracking, thermal barrier coatingTBC condition, oxidation/corrosion/erosion, hot spots/burning, missinghardware and clearance limits. Components which fall outside establishedthreshold limits are replaced to maintain optimum operating conditionsfor the entire system. If not rectified, these conditions could lead toreduced machine efficiency and damage to the turbine that may result inunplanned outages and significant repair costs.

Removal and installation of transition pieces is the most time-intensiveoperation of the combustion inspection. This operation contributes mostsignificantly to the combustion inspection outage duration andcorresponds directly to time lost producing power. To remove transitionpieces, all upstream components must be removed, i.e., fuel nozzles,water injectors and various other hardware. Each transition piece isthen dismounted and removed one by one in sequence through two accessopenings in the turbine casing. It will be appreciated that for certaingas turbines, there can be as many as fourteen transition piecesrequiring removal.

To date, recommended practice has been to remove the transition piecesand other combustion components to facilitate inspection andrefurbishment. Inspection has consisted primarily of visual methodsconsisting of the unaided eye with auxiliary lighting. Visual methods inknown problem areas have been enhanced with the use of liquid red dyepenetrant to improve visibility of small hairline cracking. Theseinspections have typically been performed offline of the combustioninspection process. Such prior inspection practices have manydisadvantages, including the time required for disassembly andinstallation, the lack of direct retrievable defect data for engineeringevaluation and historical comparison and complete reliance on humanfactors. Accordingly, there is a need for more efficient methods toinspect the transition pieces of the gas turbine combustion systems tominimize outage times while providing an accurate assessment of thecondition of each transition piece.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with a preferred embodiment of the present invention,there is provided a robotic inspection system for gas turbine combustioncomponents comprised of three robotic manipulators with miniaturecameras and lighting for inspecting various parts of the transitionpiece of each combustor in situ. The manipulators are driven remotelyusing a combination of automated and manual motion control to positionthe inspection heads, e.g., video cameras, lighting and/or measuringdevices, to various locations about and in the combustor enabling adetailed visual inspection of its transition piece and flow sleevewithout disassembly and removal of these components from the turbine.The robotic inspection system hereof is thus intended for use during agas turbine maintenance outage.

Particularly, the robotic inspection system hereof includes three tools,i.e., an exterior manipulator, an interior manipulator and an annulusmanipulator. It will be appreciated that the transition piece includesan outer impingement sleeve, typically perforated, and an interiortransition piece body defining generally an annulus therebetween. Theforward ends of the transition piece body and impingement sleeve aregenerally circular in configuration with top and bottom sides beingflattened progressively toward the first-stage nozzle. The exteriormanipulator is deployed for inspection of the external surfaces of theimpingement sleeve and has seven distinct motions. The exteriormanipulator includes a segmented arcuate rail movably mounted on acarriage disposed within the casing of the turbine, the carriage beingsupported externally of the casing by a mast. When all of the arcuaterail segments are connected end-to-end to one another, the rail extendsin excess of 90° such that an inspection head forming part of a roboticinspection subassembly carried on an end segment can inspect top, bottomand side surfaces and along the entire length of each impingement sleevein a quadrant of the annularly arranged combustors.

The robotic inspection subassembly on the end segment mounts a generallyaxially extending rail on which is mounted an upper arm. The rail ismovable in a circumferential direction with the arcuate segments as thelatter are displaced circumferentially along the carriage to locationsradially outwardly of the impingement sleeves and within the interiorsurface of the casing. The upper arm is pivotable relative to the railabout a first axis to extend between adjacent impingement sleeves andcarries at its distal end a pivotally mounted forearm. The upper arm isalso rotatable about its long axis such that when the forearm isextended, the inspection head carried at the distal end of the forearmcan be located between and radially inwardly of an impingement sleevefor inspection of its radial inner surface. The inspection head isrotatable about pan and tilt axes relative to the forearm and includes avision module, e.g., one or more cameras and a lighting system. Withthis arrangement, the inspection head can be located to inspect theentire peripheral surface of each impingement sleeve of the cannularcombustion system. A video micrometer external to the tool may be usedin conjunction with the vision module to effect measurements.

The interior manipulator is mounted to the aft combustion casing forinspecting the interior surface of the transition piece body. Theinterior manipulator includes an elongated arm carried in a sphericalbearing in a mount secured to the casing flange. The interior end of thearm carries an inspection head similar to that of the exteriormanipulator. The arm projects through the mount exteriorly of the casingand is pivoted by two linear actuators coupled between the mount and thearm to locate the inspection head adjacent the interior surface of thetransition piece body. The arm also carries concentric inner and outertubes. Actuation of an electric motor carried by the outer tube extendsand retracts the inner tube carrying the inspection head. The inner tubecarries pan and tilt motors such that the inspection head can be rotatedabout pan and tilt axes for visual inspection of the interior surfacesof the transition piece body.

The annulus manipulator includes a manually positioned inspection headfor inspecting the side seam welds along the exterior surface of thetransition piece body in the annulus between the transition piece bodyand the impingement sleeve. The annulus manipulator includes a supportstructure for supporting a pair of spaced guide plates each having apair of contoured surfaces, e.g., grooves in opposition to one another.The grooves generally correspond to the contours of the side seam weldsof the transition piece body. A middle carriage plate carries sets ofpins on opposite sides thereof engaging in the grooves and is movablelongitudinally along the guide plates. The middle carriage plate alsocarries side carriage plates for movement along respective laterallyfacing external surfaces of the guide plates. Each side carriage platecarries a holder for a wand tube which carries the inspection head. Withthe annulus manipulator located within the casing and the wand tubesecured to one of the wand carriers, the side carriage plates areadvanced toward the transition piece body by manually advancing the wandtube. As the side carriage plates are advanced, they follow the contourof the grooves which enables the inspection head to follow the contourof a side seam weld. Thus, by positioning the inspection head relativeto the annulus manipulator, the inspection head can be located directlyadjacent a side seam weld of the transition piece body and displacedlengthwise along the transition piece body thereby following andregistering with the contour of the weld.

It will be appreciated that the cameras for the inspection heads can beremotely and dynamically focused from a remote control station. Toaccomplish this, motorized cam assemblies are utilized that move thecamera lens. Additionally, a video micrometer subsystem is used toquantitatively dimension features appearing in the video imagery. Forexample, a pair of laser lights at a fixed distance apart areincorporated into the inspection head of the interior roboticmanipulator. The lasers provide a known size feature used to calibratethe video micrometer for any camera field of view. A similar process maybe used for the exterior manipulator, although known size features ofthe transition piece body are used as the calibration reference ratherthan lasers.

In a preferred embodiment according to the present invention, there isprovided apparatus for in situ inspection of the exterior surface of animpingement sleeve of one of a plurality of an annular array ofcombustors for a gas turbine wherein the turbine has an outer casingabout an axis of rotation of a turbine rotor and at least one openingthrough the casing for access to the impingement sleeve, comprising amanipulator having an arcuate segment and a carriage for supporting thesegment within the casing for movement in a circumferential directionabout the annular array of combustors, a rail carried by the segment, afirst arm carried by the rail for translatory movement therealong andpivotal movement relative to the rail about a first axis generallynormal to the axis of rotation of the rotor, a second arm coupled at oneend to the first arm for pivotal movement about a second axis normal toa plane containing the first arm and the second arm and an inspectionhead carried by the second arm adjacent an opposite end thereof forpivotal movement about pan and tilt axes perpendicular to one another.

In a further preferred embodiment according to the present invention,there is provided apparatus for in situ inspection of the exteriorsurface of an impingement sleeve of one of a plurality of an annulararray of combustors for a gas turbine wherein the turbine has an outercasing about an axis of rotation of a turbine rotor and at least oneopening through the casing for access to the impingement sleeve,comprising a manipulator having an arcuate segment and a carriage forsupporting the segment within the casing for movement in acircumferential direction about the annular array of combustors, a railcarried by the segment, a first arm carried by the rail for translatorymovement therealong and pivotal movement relative to the rail, a secondarm connected to the first arm for pivotal movement, an inspection headcarried by the second arm for movement about pan and tilt axesperpendicular to one another, the segment including a plurality ofdiscrete arcuate segments connected endwise to one another and extendingarcuately about at least the one combustion and a slider for slidingalong the rail and carrying the first and second arms and the inspectionhead.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an annular array of combustorsabout a gas turbine axis;

FIG. 2 is a fragmentary side elevational view of a combustor flow sleeveand a transition piece of a combustor illustrating an access opening;

FIG. 3 is a schematic illustration of the movements of an inspectionhead of an exterior manipulator for inspecting exterior portions of theimpingement sleeve of the transition piece;

FIG. 4 is a perspective view illustrating an exterior manipulator withinthe turbine casing adjacent an impingement sleeve;

FIG. 5 is a view similar to FIG. 4 with an upper arm and forearm of theexterior manipulator rotated and extended, respectively;

FIG. 6 is an axial end view of a segmented rail forming part of theexterior manipulator;

FIG. 7 is an enlarged view of a segment of the arcuate segmented railand a support carriage therefor;

FIG. 8 is an enlarged cross-sectional view of the carriage and segmentof FIG. 7 illustrating the drive therebetween;

FIG. 9 is a side elevational view in a plane containing the axis ofrotation of the gas turbine rotor illustrating a rail mounting ashoulder gearbox, in turn mounting the upper arm and forearm of theexterior manipulator;

FIG. 10 is a plan view of the rail of FIG. 9;

FIG. 11 is an enlarged cross-sectional view of a gearbox carried by theslider on the rail of FIGS. 9 and 10;

FIG. 12 is a cross-sectional view taken about on line 12—12 in FIG. 11;

FIG. 13 is a fragmentary view of the lower end of the upper arm, itsjoint with the forearm, the forearm and inspection head mounted on theend of the forearm;

FIG. 14 is a view similar to FIG. 2 illustrating an interior manipulatorforming part of an inspection tool according to the present invention;

FIG. 5 is an enlarged cross-sectional view of the interior manipulatorof FIG. 14;

FIG. 16 is an end view of the mounting for the interior manipulator withparts in cross-section;

FIG. 17 is an end elevational view of an annulus inspection manipulatoraccording to the present invention;

FIG. 18 is a cross-sectional view of the annulus manipulator taken abouton line 18—18 in FIG. 17;

FIG. 19 is a side elevational view of the distal end of the annulusmanipulator; and

FIG. 20 is a plan view of a wand tube forming part of the annulusinspection manipulator hereof.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, particularly to FIG. 1, there isschematically illustrated an axial view of a gas turbine, generallydesignated 10, having an outer casing 12 and an annular array ofcombustors including combustion flow sleeves 14 within the casing 12.The rotational axis of the gas turbine rotor, not shown, is indicated at16. Also illustrated in FIG. 1 is an access opening or manhole 18through which an external manipulator, generally designated 20, isinserted for inspecting the external surface of each of the impingementsleeves of the transition pieces. By manipulating the externalmanipulator 20, an inspection head 22 may be displaced axially the fulllength of the impingement sleeve as well as positioned at any locationabout the entire external peripheral surface of the impingement sleeve.

Referring now to FIG. 2, there is illustrated a flow sleeve 14 and atransition piece 24, the transition piece including an impingement,i.e., perforated sleeve 26 surrounding a transition piece body 28. Body28 extends generally axially from adjacent the forward end of theimpingement sleeve 26 and is connected at its rearward end to thefirst-stage nozzle, not shown, of the gas turbine for flowing hot gasesof combustion into the first-stage nozzle. The impingement sleeve 26 andtransition piece body 28 are generally circular at their forward endsand flatten out toward their rearward ends, terminating in a generallyrectilinear opening for flowing the gases into the first-stage nozzle.The surfaces of the impingement sleeve 26 and transition piece body 28generally conform with one another and are spaced one from the other,defining a generally annular space 30 between the surfaces of the sleeveand body. As noted previously, the combustion system component and moreparticularly the transition piece inspection system of the presentinvention includes three inspection tools, namely: an exteriormanipulator, an interior manipulator and an annulus tool. The exteriormanipulator is designed to inspect the external surface of theimpingement sleeve 26 for damage to the zipper welds, aft brackets andbullhorns. The interior manipulator is designed to inspect the insidesurface of the transition piece body 28 for cracking, corrosion and thelike and particularly for ensuring that the thermal barrier coating isintact. The annulus tool inspects the exterior surface of the side seamwelds 29 securing upper and lower halves of the transition piece body toone another.

Referring first to the exterior manipulator 20, and with reference toFIGS. 4-6, manipulator 20 is inserted in sections through the accessopening 18 and includes a support carriage 32 connected to a mast 34secured externally of casing 12 to support the manipulator 20 within thecasing 12. The carriage 32, in turn, supports a plurality of arcuatesegments 36 connected one to the other and which segments extend alongan arc in excess of 90° in a plane perpendicular to the rotor axis 16.It will be appreciated that access openings 18 are provided at locations180° apart about casing 12. Accordingly, by providing an externalmanipulator having segments 36 extending in assembly in excess of 90°,an inspection head at the end of the segments 36, and having two accessopenings 18 at locations 180° apart, each of the impingement sleeves canbe inspected by the inspection head in each quadrant about axis 16adjacent an access opening 18. The distal end of the arcuate segments 36carries a robotic inspection system subassembly, generally designated 39(FIG. 6), including a rail 38 which extends in a general axial directionrelative to the turbine rotor axis 16. Rail 38, in turn, carries aslider 40 (FIG. 10) mounting a shoulder gearbox 42 (FIGS. 11 and 12).Projecting from gearbox 42 is an upper or first arm 44 (FIG. 13)pivotally carrying a second arm, i.e., a forearm 46. At the distal endof forearm 46 is an inspection head 48 mounted for movement axiallyrelative to forearm 46 and in pan and tilt directions.

To facilitate an understanding of the movements of the externalmanipulator 20 prior to describing its component parts, the variousmotions of the external manipulator will be described with respect toFIG. 3. The rotational axis of the gas turbine is indicated 16 in FIG.3. The arcuate segments 36 lie in a plane perpendicular to axis 16. Therail 38 extends generally parallel to axis 16 and moves with the arcuatesegments 36 in a circumferential direction about axis 16 as indicated bythe double-ended arrow 50. The shoulder gearbox 42 mounted on slider 40moves with slider 40 in a generally axial direction along the rail 38,generally parallel to axis 16, thus displacing the upper arm 44, forearm46 and inspection head 48 in a forward and aft direction generallyparallel to axis 16. This linear movement of gearbox 42 is indicated bythe double-ended arrow 52 in FIG. 3. The shoulder gearbox 42 also causesrotation of the upper arm 44, forearm 46 and the inspection head 48carried at the distal end of forearm 46 about a generally tangentialfirst axis 53, the rotary motion about first axis 53 being indicated bythe arcuate double-ended arrow 54. Gearbox 42 also rotates the upper arm44 about its long axis 45 and which rotational movement about rotationalaxis 45 is indicated by the arcuate double-ended arrow 56. Forearm 46 ispivotally mounted to the distal end of upper arm 44 for rotation about asecond axis 57 extending through the elbow joint between the upper arm44 and the forearm 46 and perpendicular to a plane containing upper arm44 and forearm 46. The rotational direction is illustrated by thearcuate double-ended arrow 58 about axis 57 in FIG. 3. It will beappreciated that axes 53 and 57 are also parallel to one another.Inspection head 48 mounted on the distal end of forearm 46 is rotatablein pan and tilt directions. That is, inspection head 48 is rotatableabout the axis 59 of forearm 46 in pan and which rotation about axis 59is indicated by the arcuate double-ended arrow 60. Inspection head 48 isalso rotatable in tilt about an axis 61 perpendicular to the axis 59 offorearm 46 and which rotation about axis 61 is indicated by the arcuatedouble-ended arrow 62. Consequently, it will be appreciated that theinspection head 48 has seven degrees of freedom of movement.

Turning now to the details of the external manipulator 20 and referringto FIGS. 6-8, it will be appreciated that the mast 34 (FIG. 6) issupported externally of casing 12 and is preferably fixed to the casing.As illustrated in FIGS. 4 and 5 and to inspect the impingement sleeve,the carriage 32 is disposed within the casing 12 and supported by mast34. Referring to FIGS. 7 and 8, support carriage 32 includes spacedmounting plates 70 and a gear carriage 72 between plates 70. Gearcarriage 72 includes a centrally located spur gear 74 driven by theshaft 76 of an electric motor 78 carried within a housing 80 secured tothe support carriage 32. Plates 70 also carry rollers 82 at oppositeends of the carriage 32 for supporting the arcuate segments 36, as wellas side rollers 84 affording lateral support for the segments. Asillustrated in FIG. 8, each arcuate segment is in the form of an I-beam86 and includes a rack gear 88 along an upper surface of the segment. Itwill be appreciated that the engagement between motor-driven gear 74carried by the gear carriage 72 and rack 88 drives the arcuate segment36 along the carriage 32.

To facilitate insertion and removal of the arcuate segments, the gearcarriage 72 is pivoted at one end about a pin 92. A spring-biased shaft94 biases the opposite end of the gear carriage 72 such that the gear 74is biased into engagement with the rack gear 88. By displacing the shaft94 upwardly in FIG. 7, the gear 74 is disengaged from the rack gear 88,enabling the segments to freely slide on the rollers 82 along thecarriage 32. Carriage 32 also includes a pair of cable guide wheels(FIG. 7) 90 for guiding electrical cables, not shown, along the arcuatesegments 36 for controlling the various motors of the externalmanipulator.

Referring now to FIG. 6, the ends of the arcuate segments 36 havedovetail connections one with the other. That is, each female dovetail83 may receive the male dovetail 85 of an adjoining segment such thatthe segments can be assembled within the casing 12. It will beappreciated that the distal end of the first inserted segment carriesthe robotic subassembly 39 including rail 38, shoulder gearbox 42, upperarm 44, forearm 46 and inspection tool 48. On the end of the distalsegment 36, a pin connection is provided to secure the distal segmentand the rail 38 to one another such that the rail 38 extends from thearcuate segment in a general axial direction (see FIGS. 3-5) and toopposite axial sides of the distal segment. The pin connection isillustrated in FIG. 10 by the female recess 96 and pin 97 coupled to asupport 99 secured to rail 38 intermediate opposite ends of the rail. Atthe distal end of rail 38 there is provided a gearbox 98 having a drivegear 100, an idler gear 101, and a driven gear 102. Gear 100 is drivendirectly by an electric motor 104 carried by rail 38. Drive gear 100drives driven gear 102 through the idler gear 101. Mounted on gear 102is a lead screw 108 extending the length of rail 38. A nut, not shown,fixed to the slider 40, is threaded about the lead screw 108. The slider40 is mounted on rail 38 by rollers whereby the slider 40 traverses thelength of rail 38 upon rotation of the lead screw 108.

Referring to FIGS. 11 and 12, the shaft 120 of the shoulder gearbox 42is keyed and secured to the slider 40 at the projecting end 121, i.e.,the shaft 120 does not rotate relative to slider 40. Consequently, theshaft 120 and shoulder gearbox 42 translate with slider 40 linearlyalong the rail 38 upon rotation of lead screw 108. The gearbox 42,however, rotates about shaft 120. To accomplish this, a gear 122 isrigidly mounted on the shaft 120, i.e., the shaft 120, gear 122 andslider 40 are rigidly connected with one another. A motor 124 is mountedon gearbox 42 and drives a gear 126 in engagement with gear 122. Sincegear 122 is fixed to shaft 120, actuation of drive motor 124 rotatesgears 126 and 122, causing the gearbox 42 to rotate about shaft 120,i.e., first axis 53 (FIG. 3).

Additionally, the shoulder gearbox includes a motor 150 (FIG. 11) forrotating the upper arm 44. The upper arm 44 is mounted on a bearing 152surrounding a fixed stub shaft 154 coupled to the housing of the gearbox 42. A thrust bearing 156 carries the upper arm 44 for rotation. Agear 158 is connected to the outer tube 160 of the upper arm 44 andengages a gear 162 on the shaft 164 of motor 150. Consequently, byactuating motor 150 in either direction, the gear drive rotates theupper arm 44 about its own axis, i.e., rotational axis 45 (FIGS. 3 and11).

Referring to FIG. 13, the forearm 46 is secured to the distal end of theupper arm 44 for pivotal movement about the second axis 57 (FIGS. 13 and3). Particularly, upper arm 44 carries a bearing sleeve 180 (FIG. 13)surrounded by a bushing 182 carried by the forearm 46. A drive pulley184 is carried on the bushing 182 and cables 186 are wrapped aboutpulley 184 for pivoting the forearm 46 about axis 57 and relative to theupper arm 44. Particularly, cables 186 are wrapped about a cable drum187 (FIGS. 11 and 12) and extend past idler rolls 185 (FIG. 11), throughan interior guide tube 188, about idler rolls 189 and about drive pulley184. To pivot the forearm 46 relative to the upper arm, a drive motor191 (indicated by the dashed lines in FIG. 12) is mounted to gearbox 42and has a drive shaft 193 carrying a gear 195. Gear 195 engages a gear197 mounted for rotation on shaft 120. Gear 197 is coupled to cable drum187. By actuating motor 191, the cable drum is rotated, driving thecables 186 and hence pivoting forearm 46 relative to upper arm 44 abovesecond axis 57.

The forearm 46 preferably includes an outer tube 190 (FIG. 13) to whichis fixed a pan motor 192 internally within tube 190. The shaft 194driven by motor 192 is connected to the proximal end of an interiorrotatable tube 196 concentric within outer tube 190. The distal end oftube 196 is connected to the inspection head 48. Thus, actuation ofmotor 192 rotates inspection head 48 about the long axis of forearm 46,i.e., about a pan axis 59 (FIGS. 3 and 13).

Within inner tube 196 is a tilt drive motor 198 which drives a shaft200, in turn coupled to a bevel gear 202. The shaft 200 is mounted in abearing 204, the outer race of which is carried by inner tube 196. Bevelgear 202 lies in meshing engagement with a driven bevel gear 204 mountedon a tilt axis shaft 206, suitable bearings being provided for the shaft206. Actuation of motor 198 thus rotates inspection head 48 about theaxis of shaft 206, i.e., about tilt axis 61 (FIGS. 3 and 13). Theinspection head 48 includes various instruments such as a camera 208 anda light assembly 210, both mounted on the shaft 206. Consequently,actuation of tilt motor 198 rotates the camera and light assembly aboutthe tilt axis to the desired positions.

In operation, the exterior manipulator carriage 32 is disposed in theaccess opening 18 of the gas turbine and secured by securing the mast 34to the casing 12. The first arcuate segment carrying the rail 38,gearbox 42, upper arm 44, forearm 46 and head 48 is inserted through theaccess opening and along carriage 32. The carriage 32 supports theassembly within the casing 12. The remaining arcuate segments 36 areconnected to one another end-to-end by the dovetail connections andpassed through carriage 32. With the upper arm 34 and forearm 46 foldedagainst one another in a retracted position paralleling rail 38 andretracted along the rail to the proximal end thereof directly adjacentthe end arcuate segment 36 as illustrated in FIG. 4, the inspection head48 can be advanced about a quadrant of the combustion casing and in acircumferential direction by actuation of motor 78 until it liesadjacent the impingement sleeve sought to be inspected. That is, thesubassembly 39 is advanced in a circumferential direction in the radialspace between the impingement sleeve 26 and the interior of casing 12until it lies adjacent the impingement sleeve to be inspected. With themanipulator in the position illustrated in FIG. 4 between adjacenttransition pieces and radially outwardly thereof, the upper arm 44 canbe rotated and forearm 46 displaced from its folded position againstupper arm 44 into positions to locate the inspection head 48 adjacentthe area of the transition piece, i.e., impingement sleeve 26, to beinspected. For example, if the area to be inspected is to one side ofthe impingement sleeve, the drive motor 124 in the shoulder gearbox 42is energized to rotate the shoulder gearbox 42 about shaft 120, i.e.,axis 53. Additionally, the cable drum 126 is rotated by actuation of themotor 191 to pivot the forearm 46 relative to the upper arm 44 aboutaxis 57 into the position illustrated in FIG. 5. Motor 104 is alsoactuated and displaces the shoulder gearbox 42 linearly along the rail38. By translating the gearbox 42 along the rail 38, the axial positionof the inspection head 48 in relation to the area desired to beinspected is obtained. Actuation of pan and tilt motors 192 and 198,respectively, position the inspection head 48 and particularly thecamera and light assembly in registration with the desired inspectionarea. Consequently, visual inspection by video camera and measurementsof the desired area are obtained. In the event the underside of theimpingement sleeve is to be inspected, the shoulder gearbox 42 isrotated about axis 53 to locate the elbow, i.e., the joint between upperarm 44 and forearm 46 below, i.e., radially inwardly of, the impingementsleeve. Motor 191 is also actuated to rotate the forearm 46 about axis57 to locate it below, i.e., radially inwardly of the impingementsleeve. Motor 150 is also actuated to rotate the upper arm 44 about itsown axis 45, thus causing the forearm 46 to swing about the axis ofupper arm 44 and below the impingement sleeve. By actuation of the panand tilt motors 192 and 198, the camera and light assembly can befocused on the area sought to be inspected. Thus, it will be appreciatedthat by selective actuation of the various motors and positioning theexterior manipulator on opposite sides of the selected impingementsleeve, the entirety of the exterior surface of each of the impingementsleeves for each combustor can be visually inspected and measurementstaken in situ. Note that the motors are all electrically driven remotelyfrom outside the turbine casing through suitable electrical connectionstherewith. The motors can be actuated manually but are preferablycomputer controlled.

Referring now to FIGS. 14, 15 and 16, there is illustrated an interiormanipulator, generally designated 200, for inspecting the interiorsurface of the transition piece body 28. Referring to FIG. 14, theinterior manipulator 200 includes a mount 202 at one end of the tool andan inspection head 204 at the opposite end of the tool carrying, forexample, a similar camera and light assembly as the exteriormanipulator. The mount 202 is in the form of a cross (FIG. 16) havinglegs 206 90° from one another. The legs 206 are mounted to the flangesof the combustion casing to secure the interior manipulator thereto. Thecentral portion 208 of the mount 202 includes a spherical bearing 210carried on a tubular section 212 projecting outwardly of the mount 202.On the inside of the mount 202 and carried by the tubular section 212 isan outer tube 214 for carrying the inspection head 204.

In order to manipulate the inspection head 216 within the transitionpiece body 28, a pair of linear actuators 220 are coupled between theouter ends of a pair of legs 206, respectively, and the outer end of thetubular section 212. Particularly, each linear actuator 220 is pivotallysecured to a clevis 222 mounted to the outer end of a leg 206. Theactuator 220 includes a motor 224 which drives a lead screw 226 engagedin a threaded nut 228 mounted on a hinge 230. The hinge 230 is, in turn,mounted on the tubular section 212. By locating the linear actuators 22090° apart, it will be appreciated that actuation of the motors 224pivots the inspection head 216 about the spherical bearing 210 towardand away from the transition piece body 28.

Additionally, by extending or retracting the inspection head 204, theinspection head can be located adjacent any interior surface portion ofthe transition piece body 28. To accomplish the telescoping movement, amotor 232 is carried by the tubular section 212. Motor 232 drives a leadscrew 234 via a shaft coupling 236. A lead screw nut 238 is secured toan inner tube 240 concentric with outer tube 214. By actuating motor 232and rotating lead screw 234 in engagement with nut 238, tube 240, whichmounts the inspection head 204, can be advanced and retracted in anaxial direction.

To rotate the inspection head 204 about its own axis, i.e., to pan theinspection head, a pan motor 242 drives a shaft 244, in turn coupled toa tube 246 carrying the inspection head 204. Thus, by actuating motor242 and rotating shaft 244, tube 246 and head 204 are rotated about theaxis of the outer tube 214. To rotate the inspection head 204 about atilt axis 248, a tilt motor 250 is provided and drives the inspectionhead about axis 248 through a shaft and beveled gear connection 250 and252, respectively, similarly as previously described with respect to theexterior manipulator. It will be appreciated that the section 212 andtubes, i.e., members 214, 240 and 246 are collectively called theinspection arm.

The operation of the interior manipulator is believed self-evident fromthe foregoing description. Upon securing mount 202 of the interiormanipulator to the flange of the combustor, actuation of the linearmotors 224 and 232 locate the inspection head 204 closely adjacent to aselected interior surface portion of the transition piece body sought tobe inspected. By actuating motors 242 and 250, the inspection head isrotated about pan and tilt axes and directed such that the lightassembly illuminates the surface portion to be inspected by the videocamera of head 204.

Referring now to the annulus manipulator illustrated in FIGS. 17-20, theinspection head which preferably carries a camera and a light assemblysimilar to the previously described inspection heads is positioned inthe annulus 30 between the transition piece body 28 and the impingementsleeve 26. The annulus manipulator is specifically configured to inspectthe side seam weld 29 along opposite sides of the transition piece body.It will be appreciated the transition piece body 28 is fabricated inupper and lower halves, with the halves being welded together along weldlines 29 which essentially follow the contour of the shaped upper andlower exterior surfaces of the transition piece body 28. To inspectthose welds 29, the annulus manipulator, generally designated 300,includes a pair of mounting plates 302 which are secured by bolts duringinspection to the flanges of the combustor casing. Between the mountinglegs 302, there is provided a pair of spaced V-rails 304. Extendingcentrally between the rails 304 is a lead screw 306, terminating at oneend in a manually rotatable knob 308 supported by one of the mountingplates 302. The opposite end of the lead screw 306 is journalled intothe opposing mounting plate 302. Lead screw 306 extends through a leadnut block 310, secured between and to a pair of spaced guide plates 314.The guide plates 314 are secured to one another by suitable spacers atlongitudinally located positions along the lengths of the plates andserve as a guide for guiding an inspection head 347 along the side seamweld 29. Additionally, rollers 316 are provided on the outside of theguide plates 314 for bearing against the rails 304 to maintain theplates 314 in extended positions from the mounting plates 302 asillustrated in FIG. 18. By operation of the knob 308, the guide plates314 can be displaced accurately toward and away from opposite sides ofthe transition piece upon insertion of the annulus manipulator into thetransition piece.

As best illustrated in FIG. 18, each of the guide plates 314 includes apair of longitudinally extending contoured surfaces, i.e., grooves 320and 322. The grooves of each plate 314 register with correspondinggrooves of the opposite plate. Disposed between the guide plates 314 isa middle carriage plate 324 which carries a pair of guide pins 326projecting from each of its opposite sides and engaging in the grooves320 and 322, respectively. It will be appreciated that the middlecarriage plate 324 is slidable lengthwise along the spaced guide plates314 and along the grooves 320 and 322 of the guide plates 314, themiddle carriage plate 324 serving as a cam follower with respect to thecontoured surfaces 320 and 322. Opposite ends of the middle carriageplate 324 mount transversely extending end carriage plates 328. Alongthe outside side faces of the guide plates 314 are side carriage plates330 (FIG. 19) which extend between the outer edges of the end carriageplates 328. Thus, the middle carriage plate 324 and end carriage plates328 form essentially an I-beam with the side carriage plates 330extending parallel to the middle carriage plate 324 and between endedges of the end carriage plates 328 along outside surfaces of the guideplates 314.

On each of the exterior surfaces of the side carriage plates 330, thereis provided an arm 332 pivotal about a pin 334. Each side carriage plate330 mounts a pair of bearings 336 through which a lead screw 338 isrotatable. Lead screw 338 is rotatable on a nut 340 pivotally carried onthe upper end of arm 332. Nut 340 is also movable vertically relative toits mounting 341 on arm 332. By rotating the lead screw, the nut 340causes the arm 332 to pivot about pin 334 to provide a finite adjustableangular movement of the inspection head, as described below.

On each side of each side carriage plate 330, there is provided amounting block 344 (FIGS. 17 and 19). A wand holder 346 is pinned to oneof the mounting 344. The lateral outer end of the wand holder 346 isadapted to receive a wand tube 348, illustrated in FIG. 20, on the endof which is mounted an inspection head 347. Head 347 includes a lightassembly 349 and a video camera 351.

A carriage handle 348 is coupled by a universal joint 350 with the leadscrew 338, the handle 348 extending the length of the annulusmanipulator for manipulation externally thereof. By rotating thecarriage handle 348, the arm 332 carrying the wand tube 348 in the wandholder 346 can be pivoted to finitely locate the inspection head 347along the weld seam 29.

In using the annulus manipulator, the mount 302 is secured to the flangeof the combustion casing, with the middle and side carriage plates 324and 330, respectively, extending into the transition piece, terminatingshort of the transition piece body 28. The wand tube 353 with theinspection head 347 is mounted to the wand holder 346 extends the lengthof the annulus manipulator. The middle and side carriage plates arejointly advanced along the guide plates 314 by pushing on the carriagehandle 348. The inspection head 347 is thus guided into the spacebetween the transition piece body 28 and the impingement sleeve 26. Asthe inspection head 347 is advanced into the annulus, the side carriageplates 330 are guided by the movement of the middle carriage plate 324along the grooves 320 and 322 to follow the contour of the side seamweld 29. With the inspection head mounted on one of the side carriageplates 330, the inspection head likewise follows the contour of the sideseam weld 29. The video camera and light assembly forming part ofinspection head 347 thus register with the side weld 29 and record theintegrity of the side seam weld. By threading or unthreading the leadscrew 338, the angle of the camera 351 and light assembly 349 can befinitely adjusted within the annulus to view appropriate areas on eitherside of the weld seam and/or to ensure registration of the camera andlight assembly with the weld. After the inspection of one side weldseam, the annulus manipulator is retracted and the wand carrying theinspection head 347 is secured to the mounting block 344 carried by theother side carriage plate 330. The plates 324 and 330 are then advancedfollowing the contours of the grooves 320 and 322 whereby the inspectionhead traverses along and inspects the opposite side weld seam.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. Apparatus for in situ inspection of the exteriorsurface of an impingement sleeve of one of a plurality of an annulararray of combustors for a gas turbine wherein the turbine has an outercasing about an axis of rotation of a turbine rotor and at least oneopening through the casing for access to the impingement sleeve,comprising: a manipulator having an arcuate segment and a carriage forsupporting the segment within the casing, said carriage mounting saidarcuate segment, for movement in a circumferential direction relative tothe carriage and about the annular array of combustors; a linearextending rail carried by said segment for circumferential movementtherewith; a first arm carried by said rail for translatory movementtherealong and pivotal movement relative to said rail about a firstaxis; a second arm coupled at one end to said first arm for pivotalmovement about a second axis normal to a plane containing said first armand said second arm; and an inspection head carried by said second armadjacent an opposite end thereof for pivotal movement about pan and tiltaxes perpendicular to one another.
 2. Apparatus according to claim 1wherein said first arm is elongated and carried by said rail forrotation about an axis extending lengthwise along said first arm. 3.Apparatus according to claim 1 wherein said second arm is elongated andis rotatable about an axis extending lengthwise along said second arm.4. Apparatus according to claim 1 wherein said second arm is elongatedand said pan axis comprises an axis parallel to an axis extendinglengthwise of said second arm.
 5. Apparatus according to claim 1 whereinsaid tilt axis lies parallel to one of said first and second axes. 6.Apparatus according to claim 1 wherein said first arm is elongated andcarried by said rail for rotation about an axis extending lengthwisealong said first arm, said second arm being elongated and rotatableabout an axis extending lengthwise along said second arm, said first andsecond axes lying parallel to one another, said pan axis extendingparallel to the rotational axis of said second arm and said tilt axislying parallel to said first and second axes.
 7. Apparatus for in situinspection of the exterior surface of an impingement sleeve of one of aplurality of an annular array of combustors for a gas turbine whereinthe turbine has an outer casing about an axis of rotation of a turbinerotor and at least one opening through the casing for access to theimpingement sleeve, comprising: a manipulator having an arcuate segmentand a carriage for supporting the segment within the casing, saidcarriage mounting said arcuate segment for movement in a circumferentialdirection about the annular array of combustors; a linear extending railcarried by said segment; a first arm carried by said rail fortranslatory movement therealong and pivotal movement relative to saidrail; a second arm connected to said first arm for pivotal movement; aninspection head carried by said second arm for movement about pan andtilt axes perpendicular to one another; said segment including aplurality of discrete arcuate segments connected endwise to one anotherand extending arcuately about at least the one combustor and a sliderfor sliding along said rail and carrying said first and second arms andsaid inspection head.
 8. Apparatus according to claim 1 wherein thefirst and second arms are pivotally carried by said rail and said firstarm, respectively, for pivotal movement about axes extending generallynormal to one another.